Mining and Processing
Mining
Mining at La Negra has historically been completed using room-and-pillar and long-hole open stoping methods.
Mining activities under the PEA will initially focus on the Valeria Zone within the existing La Negra underground workings.
Ground conditions are generally competent, with limited ground support requirements.
The PEA targets average mining rates, inclusive of waste, of approximately 2,648 tonnes per day over the life of mine.
The mine plan benefits from extensive existing underground development, while production is sourced from new mining areas.
A new mining fleet is scheduled to arrive through Q4 2026 and Q1 2027.
The mine plan incorporates stockpiling of lower-grade material and continued mine planning, grade control and dilution management.
Processing
The La Negra processing facility has a 2,500 tonne per day nameplate capacity.
The processing facility consists of a standard crushing, grinding, flotation and filtration circuit producing:
- Lead-silver concentrate
- Copper-silver concentrate
- Zinc concentrate
Crushing is completed using a primary jaw crusher with secondary and tertiary cone crushers, followed by two parallel ball milling lines for primary grinding with one additional mill for regrind.
The flotation circuit consists of three stages to recover the different concentrates.
The processing plant flowsheet has been well established and is little changed over the history of the operation, allowing operating parameters and recoveries to be well understood.
Metallurgical Recoveries
The PEA assumes the following average life-of-mine metallurgical recoveries:
| Metal | Average Recovery |
|---|---|
| Silver | 83.6% |
| Copper | 77.8% |
| Lead | 81.5% |
| Zinc | 81.9% |
Metallurgical recovery assumptions were developed from actual plant performance since restarting in 2024 through Q1 2026.
Tailings Management
The Company is installing a tailings thickener and filter press to move to filtered (dry-stack) deposition, targeted for commissioning and ramp-up in H1 2027.
Filtered deposition is designed to increase operational flexibility, improve water recovery and reduce the operation's freshwater draw.
The project will provide additional tailings capacity and support the planned increase to 2,500 tpd.
Infrastructure
The La Negra operation includes established underground mine infrastructure and an on-site processing facility.
Electrical power is supplied from the national grid through a 34 kV line to the process plant and mine facilities.
Royalties
In addition to statutory government royalties, the property is subject to two distinct royalties:
- Peñoles – 2.8%, subject to certain deductions
- Orion – 2.5%